Make the jelly the night before.
Cut the cake into rough cubes, and cover the bottom of a large bowl. You can either soak them in the alcohol beforehand, or drizzle it over later, depending how strong you want it. Throw in some jelly, custard, and fruit. Make 2-3 layers like this, then cover the top with custard. If you like, garnish with Glace
Cherries.